Intralesional administration of biological response modifiers in the treatment of localized cancer of the prostate: a feasibility study.

OBJECTIVE

The primary aims of this pilot study were to establish the feasibility of intraprostatic administration of biological response modifiers (BRMs) and to investigate the toxicity and side effects of recombinant interferon (IFN)-alpha-2b injected into prostate glands harboring cancer. A secondary goal was to perform a preliminary assessment of the antitumor effect of this treatment.

METHODS

Nine patients with histologically documented carcinoma of the prostate participated in the study. IFN was administered weekly for 5 weeks, under transrectal ultrasound visualization, with a modified gun that permitted the controlled injection of small volumes initially into the area of the tumor and later into the whole gland. Total doses of IFN ranged between 15 and 100 MU.

RESULTS

The procedure resulted in minor local discomfort, comparable to a prostatic biopsy. Side effects from the drug were those anticipated from most BRMs (chills, fever, malaise, headache, fatigue), and in every case they were minor and self-limiting to several hours. Local adverse events were limited to gross hematuria (2 patients [22%]) and hematospermia (1 patient [11%]) and resolved spontaneously within 2 weeks. Antitumor activity, a secondary goal of the study, was noted in 3 (33%) patients with limited follow-up (mean 22.5 months).

CONCLUSIONS

The results of this pilot study indicate that the intraprostatic administration of IFN-alpha-2b can be readily accomplished by the method described here and is associated with minor, self-limited toxicity. With the regimen and doses used, IFN demonstrated modest antineoplastic activity. Modifications of the schedule, routes, and amounts administered may result in enhanced therapeutic value.